Sync page

Tracked shards

Epoch

Progress

Shard Progress Status

Catchup

Header sync is a fast process, where we fetch 512 'headers' at a time from the network (basically header consists of a few hashes).
State sync is downloading the current storage state - it can take couple GB for each shard that you're tracking.
Block sync is executing all the transactions in the a block (which might take up to 1 second/block) - can be faster if blocks are not full.